Automatically reversible gear pump



March 7, 1967 T. M. KROPIWNICKI AUTOMATICALLY REVERSIBLE GEAR PUMP 2Shets-Sheet 1 Filed Sept. 1, 1964 ATTURNEY March 1967 T. M. KROPIWNICKI3,307,480

AUTOMATICALLY REVERSIBLE GEAR PUMP Filed Sept. 1, 1964 2 Sheets-Sheet 2INVENTOR. TADEK M. KR D'FIWNI'EKI "@W WZW ATTORNEY United States PatentOfifice 3,307,480 Patented Mar. 7, 1967 3 307 480 AUTOMATICALLYism/hastens GEAR PUMP Tadek M. Kropiwnicki, Syracuse, N.Y., assignor toCarrier Corporation, Syracuse, N.Y., a corporation of Delaware FilledSept. 1, 1964, Ser. No. 393,610 9 Claims. (Cl. 103-3) This inventionrelates to pumps, and more particularly, to automatically reversiblegear pumps.

Gear pumps find wide spread application as a means for circulatinglubricant in machinery as, for example, compressors and internalcombustion engines. In certain applications, however, it is essentialthat the gear pump be able to sustain undirectional flow whether pumprotation be in a clockwise direction or a counterclockwise direction;that is, that the pump be reversible. Where for example, the gear pumpis employed as a lubricant circulating means for a motor drivencompressor, the manner by which the compressor motor is connected acrossthe power terminals determines the direction of motor rotation, andhence the direction of pump rotation. I

Since the compressor lubrication system fed by the gear pump is designedfor the circulation of lubricant in one direction only, the gear pumpmust be capable of feeding lubricant in that direction whatever therotational direction of the pump might be as a result of compressordrive motor rotation if the compressor is to be lubricated.

It is a principal object of the present invention to provide a new andimproved automatically reversible gear type pump.

It is an additional object of the present invention to provide a geartype pumping mechanism, which, on reversal in the direction of pumprotation, effects immediate and foolproof reversal of the pumpcomponents to maintain unidirectional flow of the fluid being pumped.

It is an object of the present invention to provide an economical gearpump having a minimum number of parts eifective to accommodate reversalsin the direction of rotation of the pumping mechanism to sustaincontinuous output of pressurized fluid.

It is an object of the present invention to provide a gear pumpincorporating a simplified reversing mechanism.

It is a further object of the present invention to provide an improvedautomatically reversible gear type pumping mechanism having reducedinternal friction.

This invention relates to an automatically reversible gear pumpmechanism comprising a rotatable internally toothed first gear; movablesupport means including a gear carrier member rotatable within theperiphery of the first gear about the axis of the first gear, the axisof the gear carrier member being parallel to and spaced from the axis ofthe first gear, means limiting rotation of the gear carrier member to apredetermined arc; an externally toothed second gear rotatablypositioned on the gear carrier member in meshing engagement with thefirst ear, the first and second gears when rotated forming intake andexhaust spaces therebetween; means for rotating the first gear; suctionport means in the support means opposite the intake space formed by thefirst and second gears; and discharge port means in the support meansopposite the discharge space formed by the first and second gears.

Other objects will be apparent from the ensuing description and drawingsin which:

FIGURE 1 is a sectional view of the pump assembly taken along lines 1-1of FIGURE 2 illustrating one embodiment of the invention;

FIGURE 2 is a sectional view of the pump assembly along lines 22 ofFIGURE 1 illustrating the position of the pump parts on rotation in aclockwise direction;

FIGURE 3 is a sectional view similar to that of FIG- URE 2 illustratingthe position of the pump parts on rotation in a counterclockwisedirection;

FIGURE 4 is a sectional view of a pump assembly illustrating a secondembodiment of the invention; and

FIGURE 5 is a sectional view of the pump mechanism along lines 55 ofFIGURE 4 illustrating the position of the pump parts on rotation in acounterclockwise direction.

Referring to the drawings, there is shown an automatically reversiblepump mechanism embodying the invention for use as an oil pump in acompressor. It will be obvious that applicants pump mechanism may beused to pump other fluids and in different environments equally as well.

In the embodiment shown in FIGURES 1-3 of the drawings, applicantsimproved gear type pump mechanism, designated generally by the numeral2, is operatively positioned in cavity 3 of compressor bearing head 4.Bearing head 4 rotatably supports, as by bearings 6, compressorcrankshaft 7. To direct oil discharged from pump 2 to the variousrelatively movable parts of the compressor, such as bearings 6,crankshaft 7 has a lubricant feed passage 9 in communication with thedischarge side of pump mechanism 2. Lateral passage 10 in crankshaft 7directs oil from feed passage 9 to bearings 6.

Cap assembly 14, secured to hearing head 4- opposite cavity 3 bysuitable means, such as bolts 15, includes an outside cover 17 andfloating support or porting member 18. Spring 19, disposed betweensupport member 18 and outside cover 17, biases support member 18 in anaxial direction. Opening 20 in outside cover 17 communicates with asource of fluid to be pumped, for example, the compressor oil sump.

Pump support member 18 is comprised of base plate 23, backup or stopplate 24, and guide or journal plate 25 suitably secured together toform a unitary structure. Guide plate 25 includes a reduced diameterpart 26 adapted to slidably fit within the bearing head cavity 3. Theoutside dimension of part 26 is slightly less than the dimension ofcavity 3.

Support member 18 includes a generally arcuate suction port 28therethrough. Generally arcuate discharge port 29 in lguide plate 25 isopposite suction port 28.

Idler gear carrier 32 is rotatably positioned in opening 33 in guideplate 25. Opening 30 is coaxial with reduced diameter part 26 of guideplate 25. Opening 34 in backup plate 24 communicates opening 30 withdischarge port 29 in guide plate 25. The radius of that portion ofopening 34 coaxial with opening 30 in guide plate 25 is slightly lessthan the radius of opening 30- to form a generally arcuate stop surface31. Stop surface 31 cooperates with base 33 of carrier 32 to limitinward movement of the gear carrier relative to support member 18.

Base 33 of gear carrier 32 is recessed at 38. Stop pin 35, fixed to base23 of support member 18, cooperates with the opposite sides of recess 38to limit rotational movement of gear carrier 32 to approximately Gearcarrier 32 has a generally cylindrical journal part 40 protrudingtherefrom. The axis of journal part 40 is parallel to and spaced fromthe axis of carrier 32. Discharge passageway 41 in carrier 32communicates lateral opening 34 in backup plate 24 with the crankshaftfeed passage 9.

Internally toothed gear 43 is rotatably disposed within bearing headcavity 3 adjacent crankshaft 7. The outer dimension of gear 43 is lessthan the dimension of cavity 3. Gear 43 is drivingly secured tocrankshaft 7 by suitable means, such as drive pin 44. Externally toothedidler gear 45, having one less gear tooth than outer gear 43, is mountedfor free rotation on journal part 40. The eccentric relationshipestablished by the parallel but non- 3 concentric axes of rotation ofgears 43, 45 is such that full tooth engagement between gears 43, 45occurs at a single point only.

Referring particularly to FIGURE 2 of the drawings, rotation ofcrankshaft 7 in a clockwise direction as shown by the arrow, drivesmeshing outer and inner pump gears 43, 45, respectively, in a clockwisedirection. Tooth pressure between gears 4-3, 45 tends to move gearcarrier 32 in a clockwise direction against pin 35. The engagement ofstop pin 35 with one side of recess 38 holds gear carrier 32 againstclockwise movement. Lubricant drawn between the teeth of rotating gears43, 45 opposite suction port 28 discharges through port 29, thedischarged fluid passing through connecting passages 34, 41 intocrankshaft lubricant feed passage 9.

On a reversal in the direction of rotation of crankshaft 7 andcorrespondingly meshing pump gears 43, 45 from a clockwise directionshown in FIGURE 2 to a counterclockwise direction shown by the arrow ofFIGURE 3, tooth pressure between the meshing outer and inner gears 43,45, respectively, moves gear carrier 32 in a counterclockwise directionthrough an arc of approximately 180 to bring the opposite side of recess38 into engagement with stop pin 35. Operation of the pump mechanism 2is unaffected by the reversal in the direction of crankshaft rotation,lubricant from suction port 28 drawn between the teeth of gears 43, 45being discharged therefrom into discharge port 29 and the compressorlubrication system.

In the embodiment shown in FIGURES 4 and of the drawings, there isprovided an automatically reversible pump mechanism having laterallydisposed suction and discharge passageways 50, 51, respectively, incommunication with cylindrical cavity 52 in bearing head 53. It isunderstood that suction passageway 58 operatively cornmunicates with asource of fluid to be pumped such as the lubricant sump of a compressorand that discharge passageway 51 operatively communicates with suitablepassages for distributing fluid pumped such as compressor lubricant feedpassages.

Compressor crankshaft 55 is rotatably disposed in cavity 52 in bearinghead 53. Internally toothed outer pump gear 57 is rotatably disposed incavity 52 adjacent crankshaft 55. The outer dimension of gear 57 is lessthan the dimension of cavity 52. Externally toothed inner pump gear 58having one less tooth than outer pump gear 57 is positioned for rotationabout an axis offset from the axis of outer pump gear 57. Gears 57, 58have full tooth engagement at one point only. Outer pump gear 57 isdrivingly connected to crankshaft 55 by suitable means such as drive pin5%.

Cap assembly 68 includes cover 64 secured to bearing head 53 oppositecavity 52 by suitable means and floating support or porting member 65disposed within cavity 52. Suitable sealing means 61 are providedbetween cover 64 and bearing head 53. Support member 65, having an outerdimension slightly less than the dimension of cavity 52, is held againstrotational movement by suitable means such as pin 66. Spring 67 disposedin chamber 69 between cover 64 and pump support member 65 biases supportmember 65 in an axial direction.

Support member 65 is recessed at 78, 72 opposite bearing head suctionand discharge passageways 50, 51, respectively. Generally arcuatesuction and discharge ports 74, 75, respectively, in support member 65operatively communicate recesses 75 72, respectively, with meshing pumpgears 57, 58.

Generally cylindrical idler gear carrier 76 is rotatably positioned inopening 7 8 of support member 65. A suitable abutment, for example snapring 79, on support member 65 limits axial movement of gear carrier 76relative to support member 65. Stop pin 80 on support member 65cooperates with semicircular recess 82 in gear carrier 76 to limitrotational movement of carrier 76 to approximately 180.

Idler gear carrier 76 includes a generally cylindrical journal part 84having an axis parallel to and spaced from the axis of carrier 76.Journal part 84 of carrier 76 rotatably supports gear 58 in engagementwith outer pump gear 57. The eccentric relation established by theparallel but nonconcentric axes of rotating gears 57, 58, that of pumpgear 57 being the axis of carrier 76, while that of pump gear 58 is theaxis of bearing part 84, is such that full tooth engagement is obtainedbetween pump gears 57, 58 at one point only.

Passage 77 in support member 65 communicates discharge recess 72 withchamber 69. By means of passage 77', relatively high pressure fluiddischarged from the pump is introduced into chamber 69 to counteract thethrust of pump head pressure on the floating support member 65 andmaintain, in cooperation with spring 67, support memer 65, and pump gear58 journalled thereon, in operative position.

Rotation of crankshaft 55 in a counterclockwise direc tion as shown bythe solid line arrow of FIGURE 5 of the drawings, rotates meshing pumpgears 57, 58 in a counterclockwise direction. Tooth pressure betweengears 57, 55 forces gear carrier 76 counterclockwise against stop pin8%), pin 88 preventing further counterclockwise movement of the gearcarrier. Lubricant from suction port 74- drawn between the rotating pumpgears 57, 58 is discharged through discharge port into dischargepassageway 51.

Rotation of crankshaft 55 and accordingly pump gears 57, 58 in anopposite or clockwise direction, as shown by the dotted line arrow ofFIGURE 5, moves carrier 76 in a clockwise direction through an arc ofapproximately against stop pin 88. The axis of inner pump gear 58similarly moves through an arc of approximately 180 to establish thepoint of full tooth engagement between pump gears 57, 58 at a pointsubstantially diametrically opposite the point of full tooth engagementshown in FIG- URE 5 of the drawings. The rotation of gears 57, 58 in aclockwise direction draws lubricant from suction port 74 between thegear teeth for discharge through discharge port 75 into dischargepassageway 51.

By the present invention, applicant has provided a gear pump whichprovides certain reversal of the pump on a reversal in the direction ofrotation of the pump driving means; an improved gear pump having asimplified construction rendering the pump suitable for variedapplication.

While I have described a preferred embodiment of my invention, it willbe understood that my invention is not limited thereto since it may beotherwise embodied within the scope of the following claims.

I claim:

1. In an automatic-ally reversible gear pump mechanism, the combinationof a rotatable internally toothed first gear; axially movable supportingmeans; a gear carrier having an axis parallel to and spaced from theaxis of said first gear supported on said supporting means; anexternally toothed second gear rotatably positioned on said gear carrierin meshing engagement with said first gear, said first and second gearswhen rotated forming intake and exhaust spaces therebetween; means forrotating said first gear; suction port means in said supporting meansopposite the intake space formed by .Said first and second gears;discharge port means in said supporting means opposite the dischargespace formed by said first and second gears; said gear carrier beingrotatable relative to said supporting means so that, upon rotation ofsaid first gear rotating means in a reverse direction, tooth pressuresdeveloped between said first and second gears rotate said gear carrierin said reverse direction; and stop means on said supporting meansengageable with said gear carrier to limit rotation of said gear carrierrelative to said supporting means in said reverse direction to apredetermined arc whereby the intake and exhaust spaces formed betweensaid first and second gears remain substantially opposite said suctionand dicharge port means.

2. A pump mechanism according to claim 1 including means urging saidsupporting means toward said first gear.

3. A pump mechanism according to claim 2 in which said means urging saidsupporting means toward said first gear includes means for applying pumpdischarge pressure to said supporting means.

4. A pump mechanism according to claim 3 including a recess in said gearcarrier defining opposed stop surfaces, said stop means comprising a pinsecured to said supporting means having a portion disposed within saidrecess and cooperable with said recess stop surfaces to limit rotationof said carrier.

5. A pump mechanism according to claim 1 in which said discharge portmeans includes a passage in said gear carrier.

6. Fluid porting means for use with an automatically reversible pump ofthe type having meshing inner and outer gears, the inner gear beingrotatably supported by a carrier having a fluid discharge passagetherethrough for rotation about an axis offset from the axis of theouter gear, comprising in combination a journal member having suctionand discharge ports therethrough and an opening therein, said openingbeing dimensioned to rotatably receive said carrier, a stop memberhaving a suction port and a discharge opening therethr-ough engagingsaid journal member so that said journal member suction port cooperateswith said stop member suction port to form an uninterrupted suctionpassage and said journal member discharge port communicates with saidstop member discharge opening, a part of said stop member overlappingsaid journal member opening to limit axial movement of said carrier insaid journal member, and a base member having a suction porttherethrough engaging said stop member so that said base member suctionport cooperates with said journal member suction port and said basemember suction port to form an uninterrupted suction passage, said stopmember discharge opening being sized to overlap a part of said journalmember opening to communicate said carrier fluid discharge passage withsaid journal member discharge port.

7. Fluid porting means for use with an automatically reversible pump ofthe type having meshing inner and outer gears, the inner gear beingsupported by a carrier for rotation about an axis oifset from the axisof the outer gear, comprising in combination a generally cylindricalpiston-like member having an opening therein coaxial therewith forrotatably receiving said carrier, the inner gear supporting portion ofsaid carrier being adapted to protrude without one end of said member,the outer periphery of said member having first and secondcircumferentially spaced recesses therein between opposite ends thereof,said member first recess being adapted to com- .iunicate with a sourceof fluid to be pumped, said memher second recess being adapted toreceive fluid discharged by said pump, said member having suction anddischarge ports therein between said one end thereof and said first andsecond recesses, respectively, stop means for limiting insertion of saidcarrier within said member opening.

8. A pump mechanism according to claim 5 in which said supporting meansincludes a first part having an opening therethrough dimensioned torotatably receive said gear carrier and a second part engageable withsaid first part and overlaying a portion of one end of said first partopening to limit insertion of said gear carrier within said first partopening, said discharge port means including interconnecting passages insaid first and second parts, said second part passage communicating withsaid discharge passage in said gear carrier.

9. A pump mechanism according to claim 8 in which the end of said gearcarrier engageable with said second part includes a recessed portiondefining a pair of opposed stop surfaces, said support means including athird part engageable with saidsecond part, said stop means comprisingan abutment on said third part projecting through said second partdischarge passage and terminating within said gear carrier recess, saidabutment cooperating with said gear carrier stop surfaces to limitrotation of said gear carrier to said predetermined arc.

References Cited by the Examiner UNITED STATES PATENTS 1,486,836 3/1924Hill 230-138 2,151,482 3/1939 Neeson 103126 2,225,228 12/1940 Neeson.2,380,783 8/1945 Painter 103126 2,525,619 10/1950 Roth et al.

3,027,846 4/1962 Schindler 103126 3,165,066 1/1965 Phelps et al. 103126FOREIGN PATENTS 476,515 12/1937 Great Britain.

DONLEY J. STOCKING, Primary Examiner. SAMUEL LEVINE, MARK NEWMAN,Examiners. W. L. FREEH, Assistant Examiner.

1. IN AN AUTOMATICALLY REVERSIBLE GEAR PUMP MECHANISM, THE COMBINATIONOF A ROTATABLE INTERNALLY TOOTHED FIRST GEAR; AXIALLY MOVABLE SUPPORTINGMEANS; A GEAR CARRIER HAVING AN AXIS PARALLEL TO AND SPACED FROM THEAXIS OF SAID FIRST GEAR SUPPORTED ON SAID SUPPORTING MEANS; ANEXTERNALLY TOOTHED SECOND GEAR ROTATABLY POSITIONED ON SAID GEAR CARRIERIN MESHING ENGAGEMENT WITH SAID FIRST GEAR, SAID FIRST AND SECOND GEARSWHEN ROTATED FORMING INTAKE AND EXHAUST SPACES THEREBETWEEN; MEANS FORROTATING SAID FIRST GEAR; SUCTION PORT MEANS IN SAID SUPPORTING MEANSOPPOSITE THE INTAKE SPACE FORMED BY SAID FIRST AND SECOND GEARS;DISCHARGE PORT MEANS IN SAID SUPPORTING MEANS OPPOSITE THE DISCHARGESPACE FORMED BY SAID FIRST AND SECOND GEARS; SAID GEAR CARRIER BEINGROTATABLE RELATIVE TO SAID SUPPORTING MEANS SO THAT, UPON ROTATION OFSAID FIRST GEAR ROTATING MEANS IN A REVERSE DIRECTION; TOOTH PRESSURESDEVELOPED BETWEEN SAID FIRST AND SECOND GEARS ROTATE SAID GEAR CARRIERIN SAID REVERSE DIRECTION; AND STOP MEANS ON SAID SUPPORTING MEANSENGAGEABLE WITH SAID GEAR CARRIER TO LIMIT ROTATION OF SAID GEAR CARRIERRELATIVE TO SAID SUPPORTING MEANS IN SAID REVERSE DIRECTION TO APREDETERMINED ARC WHEREBY THE INTAKE AND EXHAUST SPACES FORMED BETWEENSAID FIRST AND SECOND GEARS REMAIN SUBSTANTIALLY OPPOSITE SAID SUCTIONAND DISCHARGE PORT MEANS.